Device for tensioning moving cords or strips



P A. MOIESSINGERY 2,398,547

DEVICE FOR TENSIONING MUVING CORDiS OR STRIPS Filed May a, 71942 INVEN TOR: ALBERT MOESSINGEIR BY MAE? Through this tensioning Patented Apr. 16, 1946 UNITED STATE 5 PATENT, oer-ice 1 7 DEVICE FOR TENSIONING T STRIPS MOVING COR DS Albert Moessinger, Winterthur, switzerland usignor to Sulzer Frres, Soclt Anonyme, Winterthur, Switzerland Application May 8, 1942, Serial No. 442,111 i In Switzerland August 16, 1941 T T loclaims.

Automatically-working warp let-oil motions are known in which the forward motion of the warp is adjusted in accordance with the position of a tension bar. All automatic warp let-off motions hitherto known, however, possess the drawback that each stopping andstarting of the which comes from the warp, thebearings of the tension beam are loaded, thus causing friction.

While the machine is working, the warp runs from the warp beam to thefabric. On the other hand, when the machine is brought to rest, the

warp which now has a chance to contract, threads are generally so stretched that the warp moves, or tries to move, on the tension beam quite a small amount in the opposite direction, that is towards the warp beam. T

When friction is present in the bearingsof the tension beam, the tension between the tension beam and the fabric is less after the loom comes to rest than while it is'working. This phenomenon is still moreevident when using ar-.

tiflcial silk, where the warp threads are made of relatively plastic material, and therefore are stretched and consequently contract comparatively more when the loom comes to rest. This defect makes itself much more apparent with artificial silk, in which finer threads are used withrather little distance between two weft threads; a diflerence of two or threetenths of a millimetre makes a very great difference in the density of the weft. T T T TT The invention relates to a device for tension v ing moving cords or strips, especially warps on looms, where the material to be tensioned passes over a tension beam, the beam being pivotably supported and its axis of rotation being free to move in a direction substantially at right angle thereto. The invention consistsinthat at least two tensioning forces act on the tension beam, whereby at least one of these tensioning forces is I in a plane formed tangentially to the tension beam by the cords or strip to be tensioned. One tensioning force may thereby be in the same plane as the running-on or running-off part respectively of the cords or strip to be tensioned.

The tensioning forces acting on the tension beam may be directed as a mirror image (at 180) to the directions of the running-on or, running-off cords or strip.- They will preferably 5 be transmitted by a flexible element, which passes over an are on the tension beamequal to the arcmade by thecordsor stripyto be ten-'- sioned. The flexible element which transmits the tensioningforces to the tension beammay slide on the tension beam or be flrmly connected to it.

The tensioning forces may act on the tension beam over a sector of the same size as that covered by the cords or strip to be tensioned The distances between the tensioning forces acting on the tension beam and the axis of rotation of the tensionabeam are preferably the same as those between the, running-on and running-oi! part of the cords or 'st'ripto be tensioned and said axis. T

At least the tensioning force which is in the l same plane as the part of the cords or strip running of! the tensioning beam and having to be kept at a constant tension, may be produced by weights, orby a tension spring which is adjustable in a slot inclined at 45 to the direction of the force of the spring. The magnitude of the forward motion of the cords or strip to be tengosioned is adjusted by the position of the centre of the tension beam.

A few examples of executions of the subject matter of. the invention are shown diagram matically in the drawing. i

Fig. 1 is a diagrammatic side view of a loom with a warp let-oi! motion device'according to the invention and embodying the present invention. g

Fig. 2 is a view of the tension beam and parts connectedtbereto of the loomshown in Fig. 1 and taken at a right angle to the axis of rotation of the beam. T I

Figs. 3 and 4 show modifledarrangements of thetension beam counterbaiancing system according to the invention.

The tension beam I is pivotably supported on its axis 2-. The axis 2 is fixed to tension beam levers 3, which are pivoted so that they can swivel aboutanaxis Mixed to a stationary frame 4. The warp 8 or 6' runsfrom the warp beam 1 over the guide roller I, the tension beam I, the dividing rails 9, then into the harness II and the reed II to the fabric II, which winds onto the cloth beam ll. Ropes l4, ll pass. round the tension beam I and are guided round pulley I! pivotably supported in the fixed frame 4 and kept in tension by weight I1 and spring 28.

According to the invention the directions of motion of the ropes l4, I4 are directed from the tensioning beam in mirror image to the di- .rections of the running-on and running-oil warp 6, 6; The are of'contact ofthe' warp 6, 8" round the tension beam I is consequently the same as the arc of contact of the tensioning ropes I4, I4 round that beam. By this arrangement almost all external forces which act on the tension beam through the warp and through the ropes I4, I4 are counterbalanced and, depending on the angle formed by ropes I4 and I4 and the warps 6' and Ii, act very little on the bearings 2. The resistance of the tension beam I to rotation is therefore reduced to a minimum. The sum of the moments which act on the tension beam tween the running-on and running-off parts of the warp 6 and the axis of rotation 2 of the tension beam, the tensioning forcewhich is exercised by the rope I4. will be exactly as great as the tensioning force of the running-01f part of the warp 6, and the tensioning force which is exerted by the rope I4 will be exactly as great as the warp tension of the running-on parts of the warp 6'. The magnitude of the weight Il will consequently give the exact value of the tension of the-warp 6 between the tension beam I and the fabric I2.

The axle 2 of the tension beam is further connected to a driving mechanism 22 by a rod I9, an angle lever and a rod'2I. This driving mechanism receives a rotating motion from the main shaft 25 of the loom through the shaft 23 and the bevel wheel 24. According to the position of the tension beam I or of the rod 2I respectively, the warp beam is rotated more or less quickly by the shaft '26 which connects the mechanism 22 to th warp beam I through a worm gear drive 21.

Fig. 2 showsthe tension beam I seen from the rear. It can be seen how the tension beam axle 2 is held by the two tension beam levers 3. At

the tension beam I, ropes I4 are provided which are kept in tension by a rod II on which weights I1 are arranged. Rope I4 runs to the tension beam I with the same angle of contact 11 round the beam as the warp 6.

With the arrangement according to Fig. 3, the rope I4 (Figs. 1 and 2) is replaced by a flexible element, for instance a steel strip 29. The steel strip 29 is fixed by a screw 30 on the tension beam. The upper part of the steel strip 29 is kept in tension by a spring 35, and in order that this may remain constant under all operating conditions, the following arrangement is provided:

The angle or between the spring holding device 3i and the connecting line of the spring h'olding point 32 with the point of rotation 33 of "she lever 34 is about The dimensions of the spring are suchthat its length is equal to the distance of the fulcrum of the lever 34 perpendicularly from the spring holding device 3 I.

If th warp 6 lengthens, thelever 34 will turn to the left; Consequently the spring 35 will then expand andexercise less force on the lever 34. The distance between the spring supporting device 3| and the fulcrum of the lever 34 will, however, increase, so that the torque exercised by the spring 35 on the lever 34 remains unchanged. In that way the force exerted on the tension beam I by the steel strip 23 is maintained.

. The lower part 29'of the steel strip 29 is simply held in tension by a spring 36, since it is not necessary that the tension force oi the runningon part of the warp 6', which is Just as great as the tension force of the lower part of the steel strip 23', be kept constant.

In the embodiment shown in Fig. 4 the steel strip 29 (Fig. 3) replaced by a fixed connecting rod 31 which is connected to the tension beam 38 through a joint 38 and a lever 45. The connecting rod 31 is connected to the lever 34 by a Joint. Instead of the part 23' of the steel strip 29 of Fig. 2, a rod 4| is provided in Fig. 4, whose end 42 is. connected revolvably to the lever 45, which lever is connected to the tension beam 38. The distance between the joint 39 and the axis of rotation 43 of the tension beam 39 is equal to the radius of the tension beam.

I claim:

1. A mechanism for tensioning the warp threads in looms for weaving, said mechanism comprising a tensioning beam, axle means rotatably supporting said beam and being free to move on an imaginary surface substantially parallel to the center plane of the portion ofthe warp threads rumiing oif said beam, tension means engaging said beam and comprising a member disposed in the same plane as the center plane of the warp threads running off said beam and extending from said beam oppositely to the warp threads running off said beam, and comprising a member counterbalancing said first mentionedmember and forming with said center plane the same angle as the portion of said warp threads running on said beam and extending in opposite direction from said beam.

2. A mechanism as set forth in claim 1 in which the distances of the points of engagement of said members and said beam from the center of said beam are respectively the same as the distances of the points of enga ement of said warp threads and said beam from the center of said beam.

3. A mechanism for. tensioning the warp threads in looms for weaving, said mechanism comprising a tensioning beam, axle means rotatably supporting said beam and being free to move on an imaginary surface substantially parallel to the center plane of the warp running off said beam, flexible tension means extending over said beam and comprising a portion disposed in the same plane as the center plane of the warp running oiT said beam and extending from said beam in opposite direction to the warp'threads running off said beam, and comprising a ortion counterbalancing the before mentioned portion of said tension means and forming with said center plane the same angle as the portion of said warp threads running on said beam and extending in opposite direction from said beam.

4. A mechanism for tensioning the warp threads in looms for weaving, said mechanism comprising a tensioning beam, axle means rotatably supporting said beam and being free to move on an imaginary surface substantially parallel to the center plane of the warp running off said beam, flexible tension means extending around said beam by the same length as said warp threads extend around said beam, and comprising a portion disposed in the same plane as the center plane of the warp running off said beam and extending from said beam in opposite direction to the warp threads running off said beam, and comprising a portion forming with said center plane the same angle as the portion of,

said warp threads running on said beam and extending in opposite directionfrom said beam.

5. A mechanism for tensioning the warp threads in looms for weaving, said mechanism comprising a tensioning beam, axle means supporting said beam and being free to move on an imaginary surface substantially parallel to the center plane of the warp running 011 said beam, flexible tension means slidablydisposedon said 8. A mechanism as set forth in claim 1, said loom having a stationary part, said tension means comprising an elbow member pivoted at its elbow to said stationary part, a spring mean having one endconnected with said stationary part and the other end connected with one arm ofsaid elbow member and forming an angle of substantially 45 therewith, said first mentioned member having one end connected with the other arm of. said elbow member.

9. A mechanism as set forth in claim 1, said loom having a stationary part, said tension means beam and comprising a portion disposed in the same plane as the center plane of the warp running off said beam and extending in opposite direction thereto from said beam, and comprising a portion forming with said center plane the same angle as the portion of the warp threads running on said beam and extending in opposite direction from said beam.

6. A mechanism for tensioning the warp threads in looms for weaving, said mechanism comprising a tensioning beam, axle means sup- 7. A mechanism as set forth in claim 1, in

which one of said members is of the rigid link type and is pivotally connected with said beam.

comprising an elbow member pivoted at it's elbow to said stationary part, a spring means havin one end connected with said stationary part and the other end connected with one arm of said elbow member and forming an angle of substantia1ly45 therewith, said first mentioned member being of the link type and having one end pivotally connected with the other arm of said elbow member and the other end pivotally connected with said beam.

'10. A mechanism for tensioning the warp threads in looms forweaving having a stationary part, said mechanism comprising a tensioning beam, support means for said beam free to move on an imaginary surface substantially parallel to the center plane of the warp running oif said beam, tension means engaging said beam and comprising a part disposed inthe same plane as the center plane of the warp runningofi said beam and extending in opposite directionvthereto from said beam, and comprising apart forming withsaid center plane the same angle as the portion of the warp threads running on said beam and extending in opposite direction from said beam, spring means having, individually, one end connected with said stationary, part and the other end individually connected with the ends 40 or said parts "not engaging said beam.

ALBERT MOE SSINGER. 

